The show, which has £50 million budget, is set to take audiences by storm once all 16 episodes are completed.
And George Square is the latest in a series of Scottish locations to be featured.
Based on the bestselling novels of US author Diana Galbaldon, the show follows the adventures of a 20th century nurse, Claire Randall, played by Irish model and actress Balfe, as she travels back through time from 1946 to 17th century Scotland.
George Square is being used today to shoot scenes from Clare's 1940s life.
Doune Castle, Perthshire, Culross and Loch Rannoch have also been used to film scenes from the drama.
Comparisons have been drawn between Outlander and epic drama Game of Thrones.
It features adventure, romance and references to real historical events, in particular the lead-up to the Battle of Culloden.
The adaptation of Outlander is written by Ronald Moore, best known for his work on Battlestar Galactica and Star Trek: Deep Space Nine.